Resources for 3D Additive Construction on the Moon, Asteroids and Mars Philip Metzger University of Central Florida The Moon Resources for 3D Additive Construction on 2 the Moon, Mars and Asteroids The Moon’s Resources • Sunlight • Regolith • Volatiles • Exotics – Asteroids? – Recycled spacecraft • Derived resources • Vacuum Resources for 3D Additive Construction on 3 the Moon, Mars and Asteroids Global Average Elemental Composition Elemental composition of Lunar Soil This is supplemented by lunar ice, which provides Hydrogen, Carbon and Nitrogen (plus many other elements) Resources for 3D Additive Construction on 4 the Moon, Mars and Asteroids Terminology • Regolith: broken up rocky material that blankets a planet, including boulders, gravel, sand, dust, and any organic material • Lunar Soil: regolith excluding pieces larger than about 1 cm – On Earth, when we say “soil” we mean material that has organic content – By convention “lunar soil” is valid terminology even though it has no organic content • Lunar Dust: the fraction of regolith smaller than about 20 microns (definitions vary) • Lunar geology does not generally separate these Resources for 3D Additive Construction on 5 the Moon, Mars and Asteroids Regolith Formation • Impacts are the dominant geological process • Larger impacts (asteroids & comets) – Fracture bedrock and throw out ejecta blankets – Mix regolith laterally and in the vertical column • Micrometeorite gardening – Wears down rocks into soil – Makes the soil finer – Creates glass and agglutinates – Creates patina on the grains via vapor deposition • Lunar soil is completely unlike terrestrial soil – No lunar soil simulant can meet every need – Too expensive, $10K - $100K per ton for the best simulants – We must design simulants to meet specific needs Resources for 3D Additive Construction on 6 the Moon, Mars and Asteroids Source: Yang Liu Resources for 3D Additive Construction on Construction 3DAdditive for Resources the Moon, Mars and Asteroids and Moon,theMars 7 Source: Larry Taylor Source: David McKay, NASA/JSC Boulders & Cobbles • Rock fields usually around young craters • Exposed rocks slowly “dissolve” into regolith by micrometeoroid impacts • Buried rocks can survive long times • Soil rakes may extract them from the regolith Source: http://www.ion-tracks.de/nuc/6/6/1.html Resources for 3D Additive Construction on 8 the Moon, Mars and Asteroids Soil Particle Size Distribution Credit: Khalid Alshibli Resources for 3D Additive Construction on 9 the Moon, Mars and Asteroids Soil Maturity • Soil formed by a recent impact is immature – Coarser, less glass content, fewer agglutinates, less nanophase iron • Exposure to micrometeorite garding Lunar Source: Sourcebook makes it submature then mature Resources for 3D Additive Construction on 10 the Moon, Mars and Asteroids Soil Compaction • Loose on the surface • Generally increases in compaction with depth • Looser at the rims of young craters • May be looser in the permanently shadowed craters and areas of low Source: Lunar Source: Sourcebook insolation Resources for 3D Additive Construction on 11 the Moon, Mars and Asteroids Flowability of Lunar Soil • Lunar soil does not flow well – Sharp, angular particles = high friction – Dust content = high cohesion – Low Gravity • Lunar soil simulants often flow too easily – JSC-1A flows far too easily – NU-LHT series much better but very expensive • Technologies developed to keep it from jamming – Pneumatic – Magnetic – Vibration (risk of compacting) Resources for 3D Additive Construction on 12 the Moon, Mars and Asteroids Composition of Lunar Soil • Mixture of minerals, rock fragments, glass spherules, breccias, and agglutinates • Minerals include pyroxene, plagioclase, ilmenite, basalt, etc. • Mixed laterally by impacts – Every location on the Moon contains soil particles from every part of the Moon • Nevertheless, soil composition varies both locally and regionally – Highlands vs. Mare • Can we somehow sort the minerals? (Beneficiation) Resources for 3D Additive Construction on 13 the Moon, Mars and Asteroids Magnetic Susceptibility of Lunar Soil • Particles coated with a glass patina or rim from impact vapor deposition • Rims contain nanophase iron particles, npFe • npFe is superparamagnetic, dominates among fines • Larger particles may be paramagnetic • L. Taylor’s research showed a null result (so far) in magnetic Source: Credit: Keller et al, 1999, via Larry Taylor beneficiation of minerals Resources for 3D Additive Construction on 14 the Moon, Mars and Asteroids Electrostatics of Dust • Dust becomes electrically charged via: – UV light (photocharging) – Friction (tribocharging) • Electrostatic charge can make dust cling to surfaces • Electrodynamic dust screens developed to move dust by its charge • Electrostatic beneficiation – Quinn, et al successfully concentrated desirable minerals – Others in the community have disputed this result Source: NASA Resources for 3D Additive Construction on 15 the Moon, Mars and Asteroids Mare and Highlands Mare Highlands Resources for 3D Additive Construction on 16 the Moon, Mars and Asteroids Regional Composition Variations From S. Schreiner, “Molten Regolith Electrolysis Reactor Modeling and Optimization of In-Situ Resource Utilization Systems”, PhD Dissertation, MIT, 2013. 17 Procellarium KREEP Terrane • KREEP = Potassium (K), Rare Earth Elements (REE), and Phosphorus (P) • Corresponds to region of high uranium, thorium (see map), and potassium Resources for 3D Additive Construction on Credit: NASA 18 the Moon, Mars and Asteroids Binders on the Moon? • No clay minerals – May be formed by artificial chemical weathering of plagioclase minerals – Never has been tested • Sulfur – 0.16% to 0.27% in mare soils – May be extracted (along with solar wind implanted volatiles) via heating – Lunar daytime temperatures approach its melting point • Basalt fibers have been spun from simulants but the process needs more development • Others? This is a key challenge in additive construction! Resources for 3D Additive Construction on 19 the Moon, Mars and Asteroids Lunar Volatiles • Hydrogen (H, OH, H2O) has been implanted via solar wind and other processes – 65 ppm equatorially – Averaging about 120 to 150 ppm near the poles – A monolayer or worked into the bulk? • Ice deposits in the bulk regolith inside the permanently shadowed regions (PSRs) • Possibly also surface frost in the PSRs Resources for 3D Additive Construction on 20 the Moon, Mars and Asteroids Figure 8 Overlay of epithermal* counting rates in each 2° by 2° equal area pixel poleward of ±70° with surface relief maps of the lunar poles (28). W. C. Feldman et al. Science 1998;281:1496-1500 Resources for 3D Additive Construction on 21 Published by AAAS the Moon, Mars and Asteroids LCROSS Impact • 4 to 6 MT material ejected • Volatiles comprised much as 20% of mass • Not just water – CH4, NH3, H, CO2, CO – Metals including sodium, silver and mercury • Physical state of the ice is unknown Source: NASA Resources for 3D Additive Construction on 22 the Moon, Mars and Asteroids Other resources • Asteroid remnants on the Moon? – A paper in Nature suggests 25% of asteroid impactors did not vaporize and the fragments exist in the central uplift peaks of the craters • Recycling old spacecraft parts – But the historic lunar sites (Apollo, Surveyor, Ranger, and presumably the Soviet sites) are protected for their historic and cultural value Resources for 3D Additive Construction on 23 the Moon, Mars and Asteroids Derivative Lunar Resources • Plastics made from lunar volatiles via Fischer Tropsh process • Metals refined from lunar soil • Ceramics • Processing for these derivative materials requires significant infrastructure and energy Resources for 3D Additive Construction on 24 the Moon, Mars and Asteroids Molten Regolith Electrolysis Regolith Molten Resources for 3D Additive Construction on Construction 3DAdditive for Resources the Moon, Mars and Asteroids and Moon,theMars 25 Source: Taylor, Lawrence A., and W. David Carrier III. "Oxygen production on the Moon: an overview and evaluation." Resources of near-earth space 1 (1993): 69-108. Molten Regolith Electrolysis From S. Schreiner, “Molten Regolith Electrolysis Reactor Modeling and Optimization of In-Situ Resource Utilization Systems”, PhD Dissertation, MIT, 2013. The metals and silicon will be dissolved in the iron, not separated. A subsequent processing stage such as vacuum distillation is needed to isolate elements. Resources for 3D Additive Construction on 26 the Moon, Mars and Asteroids Molten Regolith Electrolysis From S. Schreiner, “Molten Regolith Electrolysis Reactor Modeling and Optimization of In-Situ Resource Utilization Systems”, PhD Dissertation, MIT, 2013. Using reasonable assumptions, it takes 5x more energy to extract a “mongrel alloy” than to make aluminum using terrestrial bauxite Resources for 3D Additive Construction on 27 the Moon, Mars and Asteroids Fluorine Processing ofRegolith Fluorine Processing Resources for 3D Additive Construction on Construction 3DAdditive for Resources the Moon, Mars and Asteroids and Moon,theMars 28 Source: Taylor, Lawrence A., and W. David Carrier III. "Oxygen production on the Moon: an overview and evaluation." Resources of near-earth space 1 (1993): 69-108. Caustic Dissolution & Electrolysis Source: Taylor, Lawrence A., and W. David Carrier III. "Oxygen production on the Moon: an overview and evaluation." Resources of near-earth space 1 (1993): 69-108. Resources for 3D Additive Construction on 29 the Moon, Mars and Asteroids Hydrogen